This invention relates to a gas heating system for a natural gas dehydrator and other kinds of oil and gas processing equipment.
In the production and processing of oil and gas, certain kinds of equipment such as gas dehydrators of the type disclosed in U.S. Pat. Nos. 3,094,574, 3,288,448 and 3,541,763 employ gas fired heating systems which utilize variable quality gas such as propane or natural gas available at the well head or processing site. The processing equipment is often situation at remote, relatively inaccessible locations and must be reliably continuously operable without attention by operating or maintenance personnel under variable and sometimes extreme climatic conditions.
Such gas heating systems comprise an elongated burner housing containing a main gas burner unit, which is operable intermittently on demand when heat is required, and a pilot light gas burner unit which provides a continuous flame to ignite the main burner unit. One of the problems with such burner systems has been pilot light flame-out.
A source of pressure change in the burner housing, which can cause pilot light flame-out, is a downdraft in the exhaust outlet stack from a combustion chamber which results in an insufficient supply of oxygen to support combustion. In the past, combustion air for both primary and secondary air for both the main burner and the pilot light burner has been supplied through one relatively large size combustion air inlet port at the end of the burner housing. An object of the present invention is to prevent pilot light flame-out caused by stack downdrafts by providing a separate combustion air inlet port for the pilot light burner. The separate combustion air inlet port supplies the primary air to the pilot burner and is located on the side wall of the burner housing between the main combustion air inlet port and the combustion chamber. Another object is to provide an arrangement of a pilot light burner system which enables easy mounting with features of adjustment to enable reliable usage. Another object is to provide a pilot light burner tip means having a heat sink and air current shield protection against flame blowout while also providing for automatic reignition of the pilot flame after flame blowout.
In general, the invention comprises an elongated generally cylindrical tubular housing means with a combustion air inlet at one end and an exhaust stack at the other end. The housing means provides an elongated combustion air chamber adjacent the air inlet end and an elongated combustion chamber adjacent the stack end. A main gas burner unit is mounted in the housing means adjacent and parallel to the central longitudinal axis thereof with gas inlet means extending radially inwardly through the side wall of the combustion air chamber to an air-gas mixing means located in the combustion air chamber. A venturi means extends from the air gas mixing means into the combustion chamber toward the stack end and is connected by an elongated air-gas passage tube means to an ignition tip means located in the combustion chamber. A pilot light burner unit is mounted in the housing means adjacent and in parallel relationship with the main burner unit. A separate pilot gas inlet means and a separate pilot primary air inlet means extend radially inwardly through the side wall of the combustion air chamber to an air-gas mixing chamber means, including an adjustable gas nozzle discharge device, which is closed relative to the main burner combustion air chamber. An adjustable elongated first pilot air-gas mixture supply tube means, including an air-gas mixing chamber and venturi means associated with the gas nozzle discharge device, extends from pilot air-gas mixing chamber means into the combustion chamber and is connected to another pilot air-gas supply tube means having an ignition tip means mounted on the end thereof adjacent the main burner ignition tip means. The ignition tip means has a sleeve means circumjacent a burner means to provide a heat sink for reignition of the pilot flame and to protect against flame out due to air currents.